Spin-Canting-Induced Band Reconstruction in the Dirac Material ${\mathrm{Ca}}_{1\ensuremath{-}x}{\mathrm{Na}}_{x}{\mathrm{MnBi}}_{2}$

Spin-Canting-Induced Band Reconstruction in the Dirac Material ${Ca}_{1 - x} {Na}_{x} {MnBi}_{2}$

R. Yang, M. Corasaniti, C. C. Le, Z. Y. Liao, A. F. Wang, Q. Du, C. Petrovic, X. G. Qiu, J. P. Hu, and L. Degiorgi

Phys. Rev. Lett. 124, 137201 – Published 30 March 2020

Abstract

The ternary $A {MnBi}_{2}$ ( $A$ is alkaline as well as rare-earth atom) materials provide an arena for investigating the interplay between low-dimensional magnetism of the antiferromagnetic MnBi layers and the electronic states in the intercalated Bi layers, which harbor relativistic fermions. Here, we report on a comprehensive study of the optical properties and magnetic torque response of ${Ca}_{1 - x} {Na}_{x} {MnBi}_{2}$ . Our findings give evidence for a spin canting occurring at $T_{s} \sim 50 - 100 K$ . With the support of first-principles calculations we establish a direct link between the spin canting and the reconstruction of the electronic band structure, having immediate implications for the spectral weight reshuffling in the optical response, signaling a partial gapping of the Fermi surface, and the dc transport properties below $T_{s}$ .

Received 12 November 2019
Revised 12 February 2020
Accepted 6 March 2020

DOI:https://doi.org/10.1103/PhysRevLett.124.137201

Physics Subject Headings (PhySH)

Density of states First-principles calculations Magnetic coupling Spin torque Topological materials

Magnetic techniques Optical spectroscopy

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

R. Yang¹, M. Corasaniti¹, C. C. Le², Z. Y. Liao^3,4, A. F. Wang^5,*, Q. Du ^5,6, C. Petrovic^5,6, X. G. Qiu ^3,4,7, J. P. Hu^3,8,9, and L. Degiorgi ¹

¹Laboratorium für Festkörperphysik, ETH—Zürich, 8093 Zürich, Switzerland
²Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany
³Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
⁴School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
⁵Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
⁶Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11790, USA
⁷Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
⁸Kavli Institute for Theoretical Sciences and CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
⁹South Bay Interdisciplinary Science Center, Dongguan, Guangdong Province 523808, China